As it took me sometime to have it working as I wanted, I thought some other could be interested.I hope somebody can benefit from this.

Few months back I saw this guy who created a project where when the mailman opens the mailbox, it sends a message onto a smartphone.I have no clue if I'm going to use this but I found it funny ;-)For the moment it's a button that simulates the opening of the mailbox and I used Prowl on my iPhone to be notified.